[asterisk-commits] tilghman: branch 1.8 r307793 - in /branches/1.8: ./ res/res_odbc.c

[SVN commits to the Asterisk project]

Author: tilghman
Date: Mon Feb 14 14:16:55 2011
New Revision: 307793

URL: http://svnview.digium.com/svn/asterisk?view=rev&rev=307793
Log:
Merged revisions 307792 via svnmerge from 
https://origsvn.digium.com/svn/asterisk/branches/1.6.2

........
  r307792 | tilghman | 2011-02-14 14:10:28 -0600 (Mon, 14 Feb 2011) | 8 lines
  
  Increment usage count at first reference, to avoid a race condition with many threads creating connections all at once.
  
  (issue #18156)
   Reported by: asgaroth
   Patches: 
         20110214__issue18156.diff.txt uploaded by tilghman (license 14)
   Tested by: tilghman
........

Modified:
    branches/1.8/   (props changed)
    branches/1.8/res/res_odbc.c

Propchange: branches/1.8/
------------------------------------------------------------------------------
Binary property 'branch-1.6.2-merged' - no diff available.

Modified: branches/1.8/res/res_odbc.c
URL: http://svnview.digium.com/svn/asterisk/branches/1.8/res/res_odbc.c?view=diff&rev=307793&r1=307792&r2=307793
==============================================================================
--- branches/1.8/res/res_odbc.c (original)
+++ branches/1.8/res/res_odbc.c Mon Feb 14 14:16:55 2011
@@ -1218,13 +1218,14 @@
 		if (obj) {
 			ast_assert(ao2_ref(obj, 0) > 1);
 		}
-		if (!obj && (class->count < class->limit) &&
+		if (!obj && (ast_atomic_fetchadd_int(&class->count, +1) < class->limit) &&
 				(time(NULL) > class->last_negative_connect.tv_sec + class->negative_connection_cache.tv_sec)) {
 			obj = ao2_alloc(sizeof(*obj), odbc_obj_destructor);
 			if (!obj) {
 				class->count--;
 				ao2_ref(class, -1);
 				ast_debug(3, "Unable to allocate object\n");
+				ast_atomic_fetchadd_int(&class->count, -1);
 				return NULL;
 			}
 			ast_assert(ao2_ref(obj, 0) == 1);
@@ -1235,14 +1236,18 @@
 			if (odbc_obj_connect(obj) == ODBC_FAIL) {
 				ast_log(LOG_WARNING, "Failed to connect to %s\n", name);
 				ao2_ref(obj, -1);
+				obj = NULL;
 				ast_assert(ao2_ref(class, 0) > 0);
-				obj = NULL;
+				ast_atomic_fetchadd_int(&class->count, -1);
 			} else {
 				obj->used = 1;
 				ao2_link(obj->parent->obj_container, obj);
-				ast_atomic_fetchadd_int(&obj->parent->count, +1);
 			}
 		} else {
+			/* If construction fails due to the limit (or negative timecache), reverse our increment. */
+			if (!obj) {
+				ast_atomic_fetchadd_int(&class->count, -1);
+			}
 			/* Object is not constructed, so delete outstanding reference to class. */
 			ao2_ref(class, -1);
 			class = NULL;